The SONY DMR-4000 Digital Master Recorder was a professional unit designed to work with digital audio processors like the Sony PCM-1630, which was a pivotal device in mastering audio CDs during the early 1980s and part of a system used to create high-quality PCM recordings.
The features of the SONY PCM-1630, which are indicative of its performance when used with the DMR-4000, include two-channel digital audio processing with 16-bit linear quantization and switchable sampling frequencies of 44.1kHz and 44.056kHz. It boasts a wide frequency response from 20Hz to 20kHz and a dynamic range greater than 90dB. The harmonic distortion was impressively low at less than 0.05%, and wow and flutter were below the measurable limit.
The DMR-4000, based on the U-matic video cassette system, when combined with the PCM-1630, represented a significant step in the advancement of digital recording and playback technology, providing a robust system that was used for the production and mastering of many of the first CDs.
